Double-biting ring pipe coupling



Nov. 2, 1954 P. D. WURZBURGER 2,693,375

DOUBLE-BITING RING PIPE COUPLING Filed Jan. 25, 1955 FIG. I

INVENTOR.

PAUL D; WURZBURGER 25W KM;

ATTORNEYS United States Patent 9 DOUBIiE-BITING RING PIPE COUPLING.

Paulzl).\Wurzburgen ClevelamL Heights,. hiw

Application January 23; 1953,.Serial-No. 332,953-

4 Claims. (ClL.Z8'5-.--122),.

. nectednfrom theibodyqor:inst-rumentality. -with whichrit is connected-or 'associatedwvithont substantial longitudi nahrnotion orndisplacement; to-provide a novel and ima proved .sealing and:gripping element'to. seal. and grip thetubczzto be coupled more efii'ectivelyand wvithout, Or with less,hazard',. of constricting;.Ihimwalled" tubeaundesirably' or :cutting ;into they wall,- of the-tube: more :deeply than .is necessary 'or desirable; tO'iPITOV-ldfinfi coupling with amore eflicient cutting edge .andnactioni-i and correspondingly lessened wren'ch: torque; .to provide; aacoupling; which during thewoperation ob making the .joint1 .willirefiect a. feeltzi to: the operators.thattthenjoint has been; completed as by a;marked-increaseiniwrenchrtorqueyto provide a coupling that". does. notsrequirei the. provision of: a flared 40 month. or conicali camming surface interiorly of. the body member; to .provide ai couplinglelement useful in. asso-: ciation'zwith standard orttflangedx ivalve :bodies and. other instrumentalitiesz-without speciallyy machiningv the same;- to"provide a coupling that isi highly resistant to failure or deterioration from=the deleterious influences of vibration; I to provide a coupling having- "an: improved cutting edgeadapted I to turn up a ridge of l appreciable size 'fromthe wall of the tube or piece to be coupled more effi ciently -and with a -better cutting action and also'torestrictthe-depth ofnthecut and-the siZe of-theridgeand at "the-same time to gripandjconfine gthe ridge:- and to grip the tube-adjacent the' ridge andat a spaced distance from the cutting-{edge 'wherebytoenhance the grip' upon the tube-andmore'firmly' securez-the tube mechanically and effect-a more complete fiuid seal andwithalto limit moreqefiectively -the;:constriction' of the-tube incident to making the sealed-joint.

Otheriobjects include the provisionnofs a gripping and, sealing'elernent Within-whieh actions andrnotions may '60 be induced to. effecta: desirabl el apportionment of tube surface' cutting, gripping sealinggand "vibration resistant functions Another object is. to provide a sealing and. tube. .gririPirigelement; at least. part of which.may ,take a relatively; fixed position withlrelation.to.thetub.e or pipe withtwhichit'is'to beassociatedin the firstrinstance and may. .by displacement. and ..deformation. of .otherapartsi of the. element be worked into. fir'mmiechanical gripping and fluid'fsealing relation 10.11113 tube for permanent. attaclimentthereto for repeated connections anddisconnections;

Another object is to provide aself-contained coupling element whichwithin itselfu'nder' the .in'fluence oflongi tud'inally' acting .-compressive"forces converts and die tributesthose *fo'rces"intogripping, cutting; and sealing forces and'rnotionstoembrace the tube tobecoupledj a and .to substantially"integrate. the same in relationthereto. Other objects. are 'to provideibettertippin'g'action of the edge-carryinggring jpart ofthe couplingqelernent and an improved address of "the, cutting jedgej to the tube. wall 80 anda better distribution of radial and 'axialcornponents' 2,693,375 Patented Nov. 2, 1954 of force toetfect the tube' cutting andgrippi,ng"actions; to provide less distortion of 'the.tub"wal'l;' tobprevent? outward expansion of the forwardx'end'bf.i'thexcoupling ele'rne'nt;to' providela vibration resistant gripl onthe tube without 'intemfere'nee-:witlrthe :tube' cutting and sealing action and to provide a triple grip gand-sealiup'ontlre tube with 'a positive cut-or locked engagement .and a vibration" resistant' bearin'g j between the'tube' and the Icoupljng; elemjentJ Other. objects include. the provision ofmeans of'accom-v plishment of the foregoing objects that are economical of manufactu'ring costs and facile; enduring and .advan-"v tage ous .in' use.

Other. objects and advantages will 1 more fully and at large appear from the following description-of a .pre'- ferred form'of 'my invention, reference being ;had. to the accompanying drawings .in' which Figure- 1 is .an ele'vationpartly ,inl'ongitudinal section of :an..exemplary preferredform. of 'my invention with the parts in pre-assembled relation.

Figure .2 is. an enla'rgedfragmentary longitudinal section..-..similar totFigure ,1 iwiththenparts' in assembled and. working relation but prior. to the. working thereofr Figure 1 3 is' a view. corresponding .to'. Figure 21' with, however, the. parts worked and .'in .coupled and joined relation.

Referring now. .to the form of my invention shown in Figures .1 to. 3 Iinclusi've,. ,there .is. shown .an externally threaded'.body Bltoithe. rearward end'of which the tube T is.ito .be.coupled,and joined-..by the coaction .of. the in'-. ternally' threadedhut N. between whiclnand the body the coupling 1 element. 1B is} worked .into' tube t gripping and sealing relation .and into sealing, relation {with l the. .rearwardfend offthe bodyl, ThebodyB hasa bore 1.co-. extensive withzthe boreofthembe .T'and of correspond. ing. inside'vdiameternv The rearward Ifa'ceZ ofwthevbodyi may, to. take-advantage of. my iriventio'n be substantially i flat. and planar. and. lie. normal to-the axislof th'ebore of! the .body and thereby .faCili'ttteaJcldsef. coupling... The. rearward face 2 of the body serves as a longitudiiialjort axial. abutmentwfor .thefotwardv end .ofwthe tube TTre straining. .it against E axial movement toward 4 the body and. also serves asan .abutmentfdrlh forward. end. of the coupling element E holdiirglh. .forward 1 endof: thev ele-. mentagainst -forwardaxial.movement.

TlienutNl ha-s .a ;bore 5,coaxial.withlthe axis :of the 1 bore. of thebod-yiand coaxial/of. thetube andclosely and A freely encompassing. the tube; and for particular: coaction in myin'vention the tnutthas aforwardly facingdncliri'ed, preferably substantially conical female seat on cammingt shoulder. 6Angageable' ;with*theicompleinentarily formed but. more steeplyflpitithdmale shoulder-.7 omthe outer andhrearwardend of fthetcouplingifilement Ell. For-.the..: mo'st advantageous practice aof my inventioniwI Tprefer, that-the :femal'e'. sl'ibulderafi ofwthe':nuttbe pitchedsattabout. 25' tol, -30 I whilstathe:male -shou1der.- 7 "of/the coupling elementibe pitched'fiat aboutt45" to provide a. difle'rentialr angle of between: about 15-" to 20? "to facili-LI tatev the .working gofthe element and engagement of: the k tubeuthereby in particulars and with results more fully desoribedtbelowr The nut' N; and body B K areaotherwise shownain; their conventional-forms. and: I shal1'.'use-theterms nutz-andtkbody to comprehend "equivalent instru-.. mentalities...such as sanfiangedl bodyfland lanflange ring.- specifically shown. (in my =co pending. application; sucha flanged.body. .having,-. however, a :rearward, preferably; flush; tfa'cetcorresponding to the I face. =2 zand the flange ring ahaving -a ..carnn1ing shoulder correspond-ihgto the shoulder, 6, .tboth ,.forl, coaction t with! the-element E. and. tube .T,as. suggested above-wand more .fully described below 7 The coupling elementu-Ercomprises a ,rearwardlydis-1 posedannular: I relatively. thiclcsringl, part 10. :havingathe-toutward and: rearward inclined; preferably.-substantiallyt conical: surface:r.7"mentioned above, and comprises aforwardly disposed relatively-thin walled tubular on sleeve part 11' witl'1" an annular-thickened anchor portion-v or i abutment :8-at its forward end;tthe-ring part engaging:

the nut? and the anchor portion at the" forward 'end f ofi 3 parts are preferably integrally formed as shown, preferably from rod stock or tubing, so as to have or be susceptible or acquiring the qualities of resilient yielding strength in the sleeve and constrictable toughness and hardness in the ring part to perform their respective oflices and functions within my invention.

A main function of the ring part is to grip and engage the tube T with a strong mechanical grip and preferably also with a fluid tight seal. A main function of the sleeve part is to first offer sufficient axial resistance to movement of the ring part when the latter is engaged by the nut to develop inwardly acting radial components of force between the nut and the ring to induce constriction of the ring and its circular cutting edge 12, then secondly to yield both radially and axially to permit and induce inward radial and forward axial movement of the cutting edge into the wall of the tube so that the edge may turn up a ridge R of appreciable size, Fig. 3. Withal the sleeve part reacts between the nut and the body and effects a fluid tight seal with the rearward face of the body, and, as the sleeve part is foreshortened and buckled inwardly, cf. Figs. 2 and 3, it preferably forms a fluid tight seal with the ridge R and the adjacent wall of the tube. Conversely and complementarily the offices and functions of the ring part will be seen to include the transmission from the nut to the sleeve of axial components of force to compel the fluid seal between the front, preferably flat face of the anchor portion of the sleeve and the body and to foreshorten the sleeve and concurrently to transmit radial components of force from the nut to the rearward end of the sleeve to induce its inward yielding and deflection incident to its foreshortening and/or buckling into sealing and gripping engagement with the tube and ridge while it is being foreshortened. A further function of the sleeve is, preferably, that it bottoms on the ridge and tube in the sense of affording a sharp increase in resistance to movement of the nut and ring when it has been foreshortened and buckled as shown in Fig. 3 thereby limiting the cutting action of the edge 12 and notifying the operator making the joint that the desired joint has been sufficiently made by reflecting a sharp increase in wrench torque applied to the nut.

Turning now more particularly to the structure of the element E, the ring thereof has a cylindrical bore 13 which terminates at its forward end in the annular edge 12 which is circular, normal to the axis of the element and of diameter. preferably just neatly clearing the O. D. of the tube T and defined at the intersection of the forward end of the bore with the steeply pitched conical surface 14; the latter being pitched at about 80 to 75 from the same axis whereby to incline rearwardly and outwardly from the edge 12 about 10 to 15 from the plane of the edge normal to the axis of the element. The edge 12 and the adjacent stock of the ring therefore comprise in effect an annular cutting tool with about l0l5 rake angle, about 75 to 80 cutting angle and, initially, with only a nominal relief angle and clearance, regarding the tube as the work and the ridge R as the chip. As will presently appear, the ring 10 is rolled forwardly in the operation of my invention to provide a desirable relief angle and clearance for the cutting edge 12. Preferably the surface 7 of the ring is pitched at about 45 so that when and as forcible advancement of the nut toward the body is induced the ring, being first engaged by the shoulder 6 of the nut at the outer rearward corner 3 of the ring at the top of its shoulder 7, will be constrained to move and roll forwardly and radially inwardly and with the marked forward rolling and tipping action as described in my co-pending application, cf. Figs. 2 and 3. This form of my invention tolerates reasonable departures from true conicalness of the surfaces 6 and 7 so long as such departures do not deleteriously modify the operation and results of my invention as revealed in this specification as a whole; it being recognizable, of course, that the differential angle between the surfaces 6 and 7 permits and invites the ring to be rolled forwardly, decreasing somewhat the rake of the surface 14 and providing a relief angle at the forward end of the bore 13 adjacent the edge 12. The rake of the face 14 facilitates the cutting action of the edge 12 when the ring is caused to have these combined movements, causing the edge 12 to bite into the external surface of the tube and cut and turn up the ridge R with greatly increased effectiveness and facility. The height and volume of the ridge R and consequently the depth of the cut into the tube T is restricted, inter alia, by the radial dimension of the raked face 14, i. e. by the diameter of the bore 15 of the sleeve 11 adjacent the face 14. For convenience and economy of manufacture the bore 15 may be of uniform diameter as shown.

Radially outward of the edge 12 the ring 10 takes its maximum thickness and bodily mass whereby to overlie the edge and the face 14 both forwardly and rearwardly and afford good strength and support for the edge 12 as a cutting tool and to back up and support the rearward end of the sleeve 11 and to impose radial pressure upon it and upon the ridge R when the same is trapped and confined between the face 14 and the rearward end of the inwardly buckled or deflected sleeve 11 as shown in Figure 3. The external surface of the ring it) may, to conserve radial space, be cylindrical as shown for a limited distance forwardly of the corner 3 at the top of the shoulder 7; the corner 3 being annular and lying in a plane normal to the axis of the ring only a little rearwardly of the plane of the edge 12 whereby to afford good leverage to initiate the rolling of the ring, and after rolling, Fig. 3, a wide bearing between the nut and the ring at and all around the points from which the radial and axial components of force reaching the edge emanate. The mean length of the ring, as the drawings fairly show, is preferably about equal to or even a little less than the full thickness of the ring. I have observed that the rolling action of the ring 10 is such in this preferred form of my invention, cf. Figs. 2 and 3, that when the initial differential angle between the shoulders 6 and 7 is about 20 and the rake of the face 14 is about 10 to 12 the face 14 will stand about normal or retain a slight rake at the end of the rolling and cutting action as shown in Figure 3 while the shoulder 7 of the ring will have been rolled to substantial coincidence with the lesser pitch of the shoulder 6. Figure 3 also suggests as I have observed that the initial rolling of the ring and concomitant constriction of the cutting edge 12 provides an effective relief angle and clearance between the bore 13 and the surface of the tube rearwardly of the edge to initiate and facilitate a fine cutting action, especially when the face 14 is well raked; the forward end of the bore 13 taking conical form behind the edge as the constriction of the edge and cutting action proceeds. The matter of choice of materials for the coupling element in relation to the material of the tube to be coupled and the desirably greater hardness of the edge 12 than the hardness or softness of the tube is discussed more fully below.

, The sleeve part 11 of the element E in this form of my invention preferably has a radially thickened forward anchoring portion 8 with its forward face turned substantially smooth and disposed normal to the axis of the element for flush sealing engagement with the face 2 of the body. The thickened portion 8 tends to restrain the forward end of the sleeve 11 from radial expansion or contraction when the element E is worked forcibly between the nut and body. When the nut first engages the coupling element and especially before the edge 12 is forced into engagement with the tube the element tends to be rotated by the nut except as such rotation is resisted by friction and/or seizing between the rearward face 2 of the body and the forward face of the anchor portion 8 of the sleeve. This initial frictional engagement is accompanied by substantial pressure and relative motion between these faces with the bencficent result that tool marks and other small surface irregularities on these surfaces are mutually worked down or oif and a good fluid tight joint between them is etfected. My preference is that these faces be given no special anti-friction treatment or characteristic and tend to develop after limited relative seating movement, and before substantial cutting action by the edge 12 has taken place, more resistance to rotation of the element E than the rotative tendency that the nut induces through engagement between the shoulders 6 and 7; a condition which is encouraged by cadmium plating the surface 6 of the nut to facilitate its freer sliding both axially and circumferentially over and around the corner 3 and the surface 7 of the element E.

Between the anchoring portion 8 and the ring 10 the asse s-'25:

L sleeve icomprisesra thinnwalleditubulanrso called zbrid'g'e or resistantly v yieldabl'e portionii 9:: which is 1 preferably severalitimes longer. thani-its-wall. thickness withaits bore' ISneXceeding-the outsidefzdiameter' of the tubew by ap-:

proximately twice.the radialiidimension of the' face 14 to permitsradia lr inward :yieldingand/o'r buckling of f the -rearward part of :thenbridger and radial inward and axial -forwardr. cutting movement of the .edge" 12 1 until the rearward endnof the: bridge bottoms on or approaches substantial contact with the ridgesR as the same is being. or :has-rbeensturned up across rthe face '14: The bridge portioniw9 sis: :preferably';'abouta% *to as thick as \the ringsgltl and joins; the ring radially-inwardly :ot the. cemen 3 so thafi-its initial axial reaction against the ring develops' a: counterclockwise: (as viewed in :Figs.- 2. and 3) I coupleebetween the' cornert3 andwtherearward-v end of'= the bnidge which tendsato bring about the forward rolling: of the ring and constriction .ofnthecedge f1'2 'and the.in'- ward deflection and then buckling of the bridges. The

bridge hasl :sutficient initial axial strengthto provide this initial .reactionzagainst thering. and has sufl'icient radial weakness. to: facilitate: the rolling; .and constriction-bf: thetr'ringq It ist also characteristic of the bridg'e as' -it is 'proporti'oned andt:disposed-inthis form' of myv in ventionthatwits axial strength in resistance to forward motion 05- the ring :de'creases as1 inward deflection and/or:

buckling;proceedsi:whereby;to'admit forward cutting mo tiontas :wellwas 'radial inward motion. of the edge- 12 into'vrthe tube; the -:bridgc, however,: as it :is;:buckled and foreshor-te'ned under r the forcible influence of thenut through: the t ring, still offers sufficient axial reaction be tween -the rbodyand the :ring to maintain afluid tight joint:betweenitheanchorand the body and? also tolimit forward move'ment'of the ring to substantially less: move-' menta thanathe forward motion-'of the' nut so that the shoulder. 601? the nut,has=:a differential motion over the c0rner; 3--and#shou1der 7 totelfect 'a strong bodily constrictionu of the. ring uponthe tube while the. forwardand rolling motionsi and cutting actions proceed.-

In this". preferred-form. of Il'lYL il'lVBl'liiOIl there "is: pro vided-at andtintegral with the rearward inner end-of theiringe .10. a: short, thinvwalled rearward annular extension; 17 whose bore iiscoextensive withthe bore 13 of thesring-tand whose external cylindrical surface joins the lowerpart of'the camming shoulder '7'. Theouter rear-- ward corner- 18 =of*the1 extension. 17 ispreferably rounded or rtapered .off for non-scuffing ,anddelayed engagement with=the lower-part of the camming shoulder 6 of the nut v Theextension 17:is so'short that the cornerllfi. issubstantially spaced fromtheshoulder 6 whenthe corner 3 ofathe ringgis fully? engaged; isee-Fig." 2, ,sothat the corner-18 isunot engaged until tlienut' has moved for-- wardlyx appreciably With respect to the center of, massof the ring andihaswell. initiate'dthe 1 ring; rolling: and edge t-constricting and: cutting -;motions described. above; Asthe-nut: is advanced with respect 1 to the ring." and the ring:; is--rolledfforwardlyvthe forward part of the exten-' sion 17 first tends to be raised a littl'eirfrom thetube; and-about. coincidentally. -the shoulder 6 contacts. the cor -I nenils r'andabeginsto constr'ict it inwardly, forcing the rearward .end-s 'ofthei'extensio'n inwardly and forwardly toward the-tube: As 'the cuttingactionof the edge 12 andith'ex-bucklingaction'of the bridge proceed and come to intended fulfillment the rearward part of the extensionrfilT-isstrongly constricted under the rearward part of th'e shoulderr6 and forciblyconstricted upon and into tightiengagementiwith thertube, Fig. 3. The constriction of the. rearwardtpart of the extension17 with the final rolling :of: thewring r tends to'bring thev exterior surface of the extension intd-conicalvalignment with the shoulder 7'twhichihasbeenurolled to substantial conformity withsthe-shoulder. The final-constriction of the exten-- sionrll takes place' as: the/ring IOhas its last increments. of forwardimotionisoi the'inner. irear' part of the exten-. sion 17"=exertsfiaefinal Iforward working and wiping, mas

7 well- '.as -constricting;.actio'n and effect on the tube=wherewitlnto 'causei-a firmg." relatively wide vibration dampening grip'iibehind thetring proper and rearwardly'remote' from'sther cutnthat the edge hasmade'in-the tube wall.

ments of ditferential forward motion of' the nut rel'a tive to -elernent-E as a whole induce thefina-l incre' ments' of radia'l constriction of allthe parts'of the clo ment from the buckle of the bridge rearwardly into their 5 worked-and substantially integrated relation to 'the'tub'eas shownin Figure-3. These worked parts 0f=the ele=- ment-E- having been'worked and stressed beyond' their elastic lirnits persist intheir integrated relation to the tube during subsequent disconnection and recouplings upon the anaterial and character of the tube to becou pled as well as the 'materials that are desired-to be'' employed in the nut and body. My greater preference is to'use-SF A. E.-1117 steelfor the stock. of the coupling element because it is freely -rnachina bleand admits ofcase or surface hardening throughout all parts of the element including the bridgeas well a the-cutting-edge, without deleterious impairment of the flex-ibilityand workability of the flexed and worked parts characteristic ofthe mode of operation of my couplingelementt Using S. ALE. 1117 steel I do not necessarily harden the'coupling element,'other than'work hardening by the necessary machining, so long as its cutting edge -is harderthan the tube to be cut, or, as in the form of my invention shown in Fig. 4 is not required to cut thetube:

element Eprovides for the form of my invention shown in Figs. 13 a-satisfactory cutting edge and preserves desirable workability in the'other parts of the element. lesser preferance is to use other free machining steelsfor-the couplingelement E and, when used to cutpipe or 'tube's that are harder than the unhardened element;

to confine the-hardening of the-element to limited-areas I Using aluminum 13 asinthe shaded area 16 as by cyaniding and carbonitriding to have a case of as little as one to two thousandths inches deep; Dealing with stainless steel tubing, I find it practicable to harden thecutting edge and area- 16 more deeply and to a greater degree of hardness while largely avoiding hardening of the bridge and the rest 1 of the coupling element. confining the hardening to the limited area of the surface of the bore maybe done by copper plating the whole element lightly and then scuffing off the plating adjacent the edge in the bore as" v at 16' whereby to leave thebore surface uncoated and thereby exclusively exposed to the cyaniding or other hardening treatment. Alternatively the coupling element B may be completely-formed and machined andthen a rubber'tube inserted into the bore and inflated to have intimate contact with the forward portion thereof.' Thewhole element except the forward portions of the-bore 13 .theedge 12'will be free of plating and therefore exposed" to the cyaniding and hardening treatment.

To facilitate understanding and practice of my invention an example of size and proportion of the coupling element of a preferred form of my invention is statedby. 5 way of further illustration and exemplification, as follows:

For /2" O. D. tube the diameter of the edge 12 and bore 13 need exceed /2" only by enough to take care of variations. in commercialtolerance of the tube and. couplingelement to afford a free sliding fit. The O. D. of the anchoring portion 8 is about .670" and of the ring 10 is about .680". The portion 3 is about .06 long and the length of the bridge on the outer surface is about .110" long,. and, the sleeve as measured along the bore 15 from theface-14 to the forward end is about .190 long. The radial depth of the surface 14, i. e. the height of the bridge above the edge 12 is about .020" to .030", except as the same may be reducedsomewhatto limit the cutv to preserveextrauthinawalled tubing. The thickness of: thebridge -is about.016 to..0l8- and the depthof the The materiallof which the coupling element may be madeadmits of aconsiderable choice depending in part- Withsteel orstainless steel or other harder tubes the :wholly surface hardened S. A. E. 1117 steel coupling 7 groove above the bridge between the outer part of the ring and the anchor is about .038" to .048 below the top of the ring. The outer cylindrical surface of the ring is about .02" to .03 long. The overall length of the ring proper is about .09" and not much greater than or substantially the same as its maximum thickness. The extension 17 is about .040" to .050 long and about .018" thick. While the drawing in Figure 2 is not necessarily exactly at scale, I have undertaken to make it correspond substantially to the dimensions and proportions here given. For tubes of greater and smaller size my ex perience has been that all the dimensions above stated should not necessarily be modified proportionately for the best practice of my invention. For example in making a coupling element for a one inch tube the bores and the external diameters of the ring and abutment might well be approximately doubled in respect to the /2" size and the overall length might be moderately increased as in the anchor and ring, but the length and thickness of the bridge and its spacing from the tube may well be kept about the same as in the /2" size although the mean diameter of the bridge would have to be approximately doubled as compared with the /2" size. It will also be appreciated that the length of the bridge, while maintaining its desired relative length and thickness, that the radial spacing particularly of the rearward end of the bridge from the edge 12 may and preferably should be modified to increase or decrease the depth of the cut desired by the edge 12 with due regard to the wall thickness and quality of the material of the tube to be coupled and the service and pressure to which the coupling is to be subjected.

The practice and operation of this form of my invention comprises that the parts be assembled in the relation and position shown in Figs. 1 and 2; the forward end of the tube and the forward end of the coupling element E abutting the body, the camming shoulder 6 of the nut contacting the outer corner 3 of the shoulder 7 of the ring and the edge 12 substantially contacting the external surface of the tube. Thereupon the nut is forcibly advanced toward the body as through the threaded engagement therebetween and, consequently, the ring 10 is rolled forwardly and its edge 12 is simultaneously tended to be constricted inwardly and advanced axially relative to the tube and the body whilst the bridge 9 yieldingly resists axial movement of the ring sufliciently to compel its radial constriction and radial constriction of the edge 12. As the rearward end of the bridge yields to inward deflection and/or deflection and inward buckling with the constriction of the ring and cutting edge, axial forward movement of the ring and edge also takes place. Cutting engagement between the edge 12 and the tube begins at once the edge is constricted into cutting engagement therewith and may and preferably does continue under the forcible urging of the nut until bottoming occurs between the rearward end of the bridge and the ridge R as the latter is turned up by the edge 12. A direct incident of the buckling, cutting and gripping action is that the forward end of the element E is forced into fluid tight sealing relation with the rear face 2 of the body, and the rearward end of the bridge as well as the edge 12 and face 14 and the forward part of the bore 13 have fluid tight sealing contact and engagement with the tube while especially the edge 12, face 14 and the forward end of the bore 13 have and acquire a strong blow-out proof mechanical engagement with the tube. inter alia, the rearward extension 17 of the ring is constricted into tight engagement with the tube as more fully described above.

The coaction of such factors as the initial differential angle between the shoulders 6 and '7, the angle of pitch of the shoulder 6 of the nut, the rake of the face 14 and, the quality of the yielding resistance of the bridge COD-j tribute essentially and substantially to the advantages and results of this form of my invention. The angle between the shoulders 6 and 7 tends to measure the extent of the rolling of the ring while the pitch of the shoulder 6 tends to measure the apportionment between the radial and axial components initially and finally imposed on the ring as well as the differential axial motion between the nut and the ring and therefore the mechanical advantage the nut has over the ring, i. e., over the working of the whole coupling element and the cutting and gripping actions of the element on and upon the tube. Concomitantly the rake of the face 14 contributes to the ease and efficiency of the cutting action and reduces the effort, i. e. wrench torque, required for work of cutting the tube and turning up the ridge. Correlated with promoting these actions and eflects the bridge reacts against the ring to first induce and initiate the rolling of the ring which in turn deflects the rearward end of the bridge inwardly and initiates the buckling of the bridge that in turn causes the ring and more especially the edge 12 to gain forward motion along with its radial inward motion to effect the desired cutting action.

While I have illustrated and described a preferred form of my invention, changes, other modifications and improvements will occur to those skilled in the art who come to understand its uses and advantages, and therefore I do not care to be limited to the forms or illustrations of my invention herein specifically disclosed nor in any manner inconsistent with the promotion of progress in this art marked by my invention.

I claim:

1. The combination in a tube coupling of a body to the rearward end of which the forward end of a tube is coupled with said body; the tube having a first annular groove with a tapered rearward surface and an abrupt forward face spaced from the extreme forward end of the tube and having a second annular groove spaced rearwardly from said first named groove, a coupling member having a bore for the tube and forcibly coacting with said body, and a deformed coupling element forcibly gripped between said member and body and gripping the tube and having a fluid tight engagement with the tube and with said body, said member having a forwardly and outwardly inclined camming shoulder engaging the rearward end of said element, the rearward end of said element comprising a short thick substantially inflexible ringlike part with a short, thin inwardly flexed and rearwardly disposed extension part, both parts having a common outward and rearward inclined surface engaged by and constricted by the camming shoulder of said member and said ring-like part having an inwardly and forwardly tapered bore forcibly engaging said rearward tapered surface of said first groove and stressing said tube in radial compression within said bore and having a substantially radially disposed inner forward face defining an edge at the forward end of said bore and forcibly engaging the forward face of said groove and stressing said tube in axial compression toward said body, said edge being embedded in said first-named groove in the tube radially inward and substantially under said camming shoulder, said extension part having its rearward end forcibly engaging said tube in said second groove and stressing said tube in compression under a rearward portion of said camming shoulder, said element also comprising a flexible thin walled tubular part integrally formed with said ring-like part and extending forwardly therefrom from above said inner face and having an annular portion buckled inwardly upon the tube forwardly of and adjacent said first groove and compressing said tube longitudinally adjacent a forward portion of said camming shoulder.

2. The combination in a tube coupling of a body to the rearward end of which the forward end of a tube is coupled with said body; the tube having a first annular groove with a tapered rearward surface and an abrupt forward face spaced from the extreme forward end of the tube, and the tube having an annular ridge of appreciable size adjacent the forward face of said groove, the tube having a second annular groove spaced rearwardly from and adjacent said first groove, an abutment associated with said body engaging the extreme forward end of the tube, a coupling member having a bore for the tube and forcibly coacting with said body, and a deformed coupling element forcibly gripped between said member and body and mechanically gripping the tube and having a fluid tight engagement with the tube and with said body, said body having a rearward surface facing and engaging the forward end of said element, said member having a conical forwardly facing surface engaging the rearward end of said element, the rearward end of said element comprising a short thickened ring-like part of length approximating its thickness and an inwardly flexed and rearwardly disposed part shorter and thinner than said ringlike part, both parts having a common outward and rearward substantially conical surface engaged by said member and said ring-like part having an inwardly and forwardly tapered bore forcibly engaging said rearward tapered surface of said first groove and stressing said tube in radial compression within said bore and having a substantially radially disposed inner forward face defining a cutting edge at the forward end of said bore and forcibly engaging the forward face of said groove and the rearward side of said ridge and stressing said tube in axial compression against said abutment and having an outer part overhanging said face and confining and compressing said ridge, said cutting edge being embedded in said groove in the tube and said outer part compressing said ridge radially inward and substantially under a portion of said conical surface of said member, said rearwardly disposed part being forcibly constricted in said second groove and stressing said tube in radial compression under a rearward portion of said conical surface of said member, said element also comprising a flexible tubular part integrally formed with said outer part of said ring-like part and extending forwardly therefrom from above said inner face and having an annular rearward portion buckled inwardly upon the tube adjacent said ridge and in tight engagement with the tube on the forward side of said ridge and stressing the tube in compression, said element being stressed in compression axially between said member and said body and stressed in compression radially between said member and said tube.

3. A tube coupling comprising a body having a rearward face and a bore with which a tube is to have fluid connection, a coupling member having a bore through which the tube passes and having a forwardly facing outwardly flaring camming shoulder spaced from said body and movable toward the same, a coupling element having a rearwardly disposed radially and forwardly thickened axially inflexible ring part with a bore encircling the tube, said coupling element lying between said face and said shoulder, and said ring part having an inner forwardly facing substantially radial surface forming with said bore in the ring part an internal cutting edge and having a thickened annular radially outward portion overlying said surface and said edge and having a short flexible, inwardly and rearwardly disposed annular extension spaced longitudinally behind said inner surface and said edge, said coupling element also having a forward end engaging said face and an axially flexible, thin walled tubular part between said end and said ring part and yieldably resisting longitudinal movement of said ring part toward the body, said flexible tubular part lying radially between the said inner surface and the outer part of said thickened portion and being spaced from said tube, said ring part having a forwardly and outwardly inclined rearward surface rising from the forward part of said extension and of greater angle than and juxtaposed to said camming shoulder with the outer margin of said inclined surface near the radial plane of the said inner radial surface and proximate said camming shoulder, said extension lying within and being engageable by the rearward part of said camming shoulder, said flexible part resisting forward movement of said ring part of the coupling element to induce forward rolling motion of the ring part and constriction of the cutting edge into the tube and thereby flexing and weakening the flexible part and thereafter buckling the same under axial movement of the ring part of the coupling element toward said face of the body with axial and radial cutting action of said edge into the tube, and said shoulder advancing relative to said extension with the rolling motion of said ring part and forcibly constricting said extension into tight engagement with the tube behind and spaced from said cutting edge.

4. The coupling of claim 3 in which said extension is spaced from contact with said camming shoulder when said shoulder first engages the said inclined surface of the ring part whereby appreciable cutting action is had before said extension forcibly engages the tube.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,171,217 Kreidel Aug. 29, 1939 2,233,214 Lamont Feb. 25, 1941 2,452,278 Woodling Oct. 26, 1948 2,453,024 Lomelino Nov. 2, 1948 2,522,785 Hanson Sept. 19, 1950 2,585,453 Gallagher Feb. 12, 1952 2,641,487 LaMarre June 9, 1953 

